Local exploitation of a design error vulnerability in the inpview command included in multiple versions of Silicon Graphics Inc.'s IRIX could allow for arbitrary code execution as the root user.

The vulnerability specifically exists due to the fact that inpview trusts the user environment and does not drop privileges. When the environment variable SUN_TTSESSION_CMD is something such as "cp /bin/jsh

/tmp/jsh;chmod 6755 /tmp/jsh;killall -9 inpview," the chain of commands will be executed with root permissions, thus allowing a regular user to drop a setuid and setgid shell to /tmp.

III. ANALYSIS

All that is required to exploit this vulnerability is a local account and an open X display, which could be the attacker's home machine or another compromised system. Exploitation does not require any knowledge of application internals, making privilege escalation trivial, even for unskilled attackers.

IV. DETECTION

iDEFENSE has confirmed the existence of this vulnerability in SGI IRIX version 6.5.9 (feature) and 6.5.22 (maintenance). It is suspected that previous and later versions of both the feature and maintenance revisions of IRIX 6.5 are also vulnerable.

V. WORKAROUND

Only allow trusted users local access to security critical systems.

Alternately, remove the setuid bit from inpview:

chmod u-s /usr/lib/InPerson/inpview

VI. VENDOR RESPONSE

Support for the InPerson product did not extend beyond 02/2002 as notedin the following publication:

Get paid for vulnerability researchhttp://www.idefense.com/poi/teams/vcp.jsp

X. LEGAL NOTICES

Copyright (c) 2004 iDEFENSE, Inc.

Permission is granted for the redistribution of this alertelectronically. It may not be edited in any way without the expresswritten consent of iDEFENSE. If you wish to reprint the whole or anypart of this alert in any other medium other than electronically, pleaseemail customerservice@idefense.com for permission.

Disclaimer: The information in the advisory is believed to be accurateat the time of publishing based on currently available information. Useof the information constitutes acceptance for use in an AS IS condition.There are no warranties with regard to this information. Neither theauthor nor the publisher accepts any liability for any direct, indirect,or consequential loss or damage arising from use of, or reliance on,this information.